The development of new energy technologies that are simultaneously economically viable, clean, sustainable, and easily transportable has become one of the most important research goals of the 21st century. Full utilization of the largest and most obvious source of renewable energy—the sun—requires advanced technologies for converting light into other useful forms of energy, as well as novel means for storing energy for convenient transport and on-demand use. One promising concept that has recently become the focus of renewed attention is that of solar thermal fuels, which store energy from the sun in photoactive molecules. Upon absorption of light energy, a photoactive molecule adopts a higher-energy metastable state. To release the energy stored in the higher-energy state, an external trigger (such as heat, light, voltage, or a chemical reaction) is applied). The fuel can subsequently be recharged by exposure to light; in principle, the entire operation can be repeated ad infinitum.